Combine cherry tomatoes, onion, chilli and garlic in a heavy-based pan and cook over a medium heat for 2-3 minutes. Season with salt and pepper and cook until soft.
Add spaghetti to a large pan of boiling salted water, cook until al dente.
Add the prawns to the sauce and heat until prawns are cooked through.
Stir in cream and chopped basil. Warm through gently for a couple of minutes.